The entire disclosure of Japanese Patent Application No. 2014-065433, filed Mar. 27, 2014 is expressly incorporated by reference herein.
1. Technical Field
The present invention relates to an ink composition and a recording method.
2. Related Art
The ink jet recording method is able to record high definition images with a comparatively simple device, and rapid development has been made on various fronts. Among these, clogging or the like of ink jet nozzles has been variously researched. JP-A-9-249838 discloses providing a pigment type aqueous ink jet recording liquid that provides the characteristics demanded as an ink jet recording liquid, in particular excellent waterproofness, light resistance, resolution, and stable discharge, without clogging of the nozzles, and discloses an ink jet recording liquid in which a pigment and a resin are dispersed in an aqueous medium, where the resin is an aqueous emulsion formed from a gel formed from a polymer with a glass transition point of 50° C. to 150° C. and a core formed from a polymer with a glass transition point of −100° C. to 40° C.
However, JP-A-9-249838 does not disclose a difference between the glass transition temperatures of the core polymer and the shell polymer. The ink composition disclosed in JP-A-9-249838 has 0.8 mass % of pigment content (solid content conversion) and the content of the polymer particles in relation thereto is a comparatively small 2 mass % to 4 mass %. Incidentally, in a case where the content of the pigment is comparatively large, the resin ordinarily used also increases, thereby increasing the viscosity of the ink composition. In so doing, a problem arises of clogging of the nozzles easily occurring and recovery from clogging becoming difficult.
In order to record on a low-absorbency recording medium or a non-absorbent recording medium, it is preferable that comparatively large amount of polar solvent and resin is used, from the viewpoint of securing abrasion resistance. However, because the boiling point of the polar solvent is generally high, and because drying the ink composition becomes difficult when large amounts are used, a long time is necessary for drying and as a result, a problem arises of aggregation unevenness occurring. When the recording medium is heated at a comparatively high temperature in order to resolve this problem, a problem arises of deformation of the medium or clogging of the nozzles easily occurring.